All-solid-state battery production method

Abstract

The present invention provides an all-solid-state battery production method involving providing a Li metal or a Li alloy on the negative electrode side during production, and capable of improving a negative electrode utilization rate during a first discharge operation. The all-solid-state battery production method includes the steps of: forming a laminate in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer having an area larger than that of the positive electrode layer in a plan view and containing a lithium metal or a lithium alloy, and a negative electrode current collector are stacked; and performing a discharge operation on the laminate. The negative electrode layer has an opposing portion facing the positive electrode layer and a non-opposing portion not facing the positive electrode layer. The step of performing a discharge operation involves performing a discharge operation while applying a stronger stimulus to the non-opposing portion than to the opposing portion.

Description

Manufacturing method for all-solid-state batteries

[0001] The present invention relates to a method for manufacturing an all-solid-state battery.

[0002] When manufacturing an all-solid-state battery, there are cases where a positive electrode layer containing lithium is used, and cases where the positive electrode layer does not contain lithium and lithium is provided on the negative electrode side. Patent Document 1 describes a solid-state battery including a positive electrode layer, a negative electrode layer partially facing the positive electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, the solid electrolyte layer including a high ion conductivity portion located in a region where the positive electrode layer and the negative electrode layer face each other and having a relatively high ion conductivity, and a low ion conductivity portion located so as to face the positive electrode layer in a region where the positive electrode layer and the negative electrode layer do not face each other and having a relatively low ion conductivity.

[0003] International Publication No. 2018 / 203474

[0004] When a positive electrode layer containing lithium is used during manufacturing, the battery is manufactured with an SOC of 0%. Then, when the first charging operation is performed, lithium is deposited on the negative electrode side. In contrast, an all-solid-state battery in which lithium (Li) metal or a Li alloy is provided on the negative electrode side during manufacturing is manufactured with an SOC of 100%. Then, when the first discharging operation is performed, Li on the negative electrode side moves to the positive electrode side and is absorbed into the positive electrode layer.

[0005] The object of the present invention is to provide a method for manufacturing an all-solid-state battery in which lithium (Li) metal or a Li alloy is provided on the negative electrode side during manufacturing, and in which the negative electrode utilization rate is improved when performing an initial discharge operation.

[0006] A method for manufacturing an all-solid-state battery according to one aspect of the present invention includes the steps of forming a laminate in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer having an area larger than that of the positive electrode layer in a planar view and containing lithium metal or a lithium alloy, and a negative electrode current collector are stacked, and performing a discharging operation on the laminate, wherein the negative electrode layer has a facing portion that faces the positive electrode layer and a non-facing portion that does not face the positive electrode layer, and the discharging operation is performed while applying a stronger stimulus to the non-facing portion of the facing portion and the non-facing portion.

[0007] According to one aspect of the present invention, in an all-solid-state battery that contains lithium (Li) metal or a Li alloy on the negative electrode side during manufacturing, the negative electrode utilization rate during the initial discharge operation can be improved.

[0008] 1. A cross-sectional view showing an example of the configuration of an all-solid-state battery according to Comparative Example 1. FIG. 2. A cross-sectional view showing an example of the configuration of an all-solid-state battery according to Comparative Example 2. FIG. 3. A cross-sectional view showing an example of the configuration of an all-solid-state battery manufactured by the manufacturing method for an all-solid-state battery according to Embodiment 1. FIG. 4. A flowchart showing a method for manufacturing a battery according to Embodiment 1. FIG. 5. A schematic diagram for explaining steps ST1 to ST3 of the flowchart shown in FIG. 2. FIG. 6. A cross-sectional view showing an example of the configuration of an all-solid-state battery according to Embodiment 1 and a first discharge operation. FIG. 7. A cross-sectional view showing the first discharge operation when the stimulus is heat. FIG. 8. A cross-sectional view showing the planar configuration of the heater shown in FIG. 7. FIG. 9. A cross-sectional view showing the first discharge operation when the stimulus is heat.

[0009] An embodiment of the present invention (the present embodiment) will be described below. In the drawings, identical or similar parts are designated by identical or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratios of each device and each component, and the like may differ from those in reality. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. It goes without saying that the dimensional relationships and ratios of parts included in the drawings may differ from one another. The definitions of directions such as up and down in the following description are merely for the convenience of explanation and do not limit the technical concept of the present invention. For example, if an object is rotated 90 degrees and observed, up and down are read as being converted to left and right, and if it is rotated 180 degrees and observed, up and down are read as being reversed.

[0010] [Embodiment 1] <<Overview>> An all-solid-state battery 9A according to Comparative Example 1 shown in FIG. 1 includes a positive electrode layer 5A containing Li and is manufactured at a state of charge (SOC) of 0%. An all-solid-state battery 9B according to Comparative Example 2 shown in FIG. 2 includes a negative electrode layer 2A of Li disposed between a negative electrode current collector 3 and a solid electrolyte layer 8 and is manufactured at an SOC of 100%. As shown in FIG. 1 , when the all-solid-state battery 9A is subjected to an initial charging operation (hereinafter referred to as the initial charging operation) from a state in which no electrochemical operation such as charging or discharging has been performed, a negative electrode layer 2 of Li is deposited in a region of the negative electrode current collector 3 that overlaps the positive electrode layer 5A in a planar view. An advantage of manufacturing the all-solid-state battery 9B shown in FIG. 2 is that, for example, since it is not necessary to occlude Li in the positive electrode layer 5 in advance, the choice of materials for the positive electrode layer 5 can be broadened. In manufacturing the all-solid-state battery 9B, as shown in FIG. 2 , when an initial discharge operation (hereinafter referred to as the initial discharge operation) is performed from a state in which no electrochemical operation such as charge / discharge has been performed, the anode layer 2A moves to the cathode layer 5 and is occluded.

[0011] In general, the material of the positive electrode layer 5 is more expensive than the material of the negative electrode layer 2. Therefore, when manufacturing an all-solid-state battery 9B, as shown in FIG. 2 , a negative electrode layer 2A having a larger area in a planar view than the positive electrode layer 5 is provided in order to maximize the capacity of the positive electrode layer 5. However, such a negative electrode layer 2A includes a facing portion 21 facing the positive electrode layer 5 and a non-facing portion 22 not facing the positive electrode layer 5. When an initial discharge operation is performed, the reaction in the facing portion 21 tends to proceed faster than the reaction in the non-facing portion 22. As a result, the non-facing portion 22 may not fully react and remain on the negative electrode side, resulting in a void X in the region where the facing portion 21 was located.

[0012] 3 , the all-solid-state battery 1 manufactured by the manufacturing method according to the first embodiment includes an anode 4 having an anode layer 2 and an anode current collector 3, a cathode 7 having a cathode layer 5 and a cathode current collector 6, a solid electrolyte layer 8 disposed between the anode 4 and the cathode 7, an anode tab lead 11 joined to the anode current collector 3, and a cathode tab lead 12 joined to the cathode current collector 6. The all-solid-state battery laminate 10 may be covered and sealed by an exterior body (not shown).

[0013] The negative electrode layer 2 is provided on both surfaces in the thickness direction of the negative electrode current collector 3 (top and bottom surfaces in FIG. 3 ). For example, the negative electrode 4 can be obtained by pressure-bonding lithium (Li) metal or a Li alloy to both surfaces of the negative electrode current collector 3 as the negative electrode layer 2. For the negative electrode current collector 3 and the negative electrode tab lead 11, for example, a metal foil such as copper (Cu), a Cu alloy, nickel, or a nickel alloy can be used, but is not limited to these. The negative electrode layer 2 is made of Li metal or a Li alloy. More specifically, examples of Li alloys include, but are not limited to, a Li-Mg alloy, a Li-Si alloy, a Li-Al alloy, a Li-Zn alloy, a Li-Sn alloy, and a Li-Bi alloy.

[0014] The positive electrode layer 5 is provided on both surfaces in the thickness direction of the positive electrode current collector 6 (top and bottom surfaces in FIG. 3 ). For example, a positive electrode 7 can be obtained by preparing a slurry by weighing and mixing predetermined amounts of a positive electrode active material, a sulfide solid electrolyte, a conductive additive, a binder, and an organic solvent, applying the slurry to both surfaces of the positive electrode current collector 6, and then drying the slurry. The positive electrode current collector 6 and the positive electrode tab lead 12 can be made of, for example, aluminum (Al) foil, but are not limited to these. The positive electrode layer 5 can be made of, for example, manganese dioxide, sulfide, or fluoride, but are not limited to these.

[0015] The solid electrolyte layer 8 may be made of any material as long as it functions as an electrolyte layer in a secondary battery. For example, the solid electrolyte layer 8 may include a sulfide solid electrolyte. Examples of sulfide solid electrolytes include materials containing Li, phosphorus (P), sulfur (S), and a halide. For example, the solid electrolyte layer 8 can be obtained by weighing and mixing predetermined amounts of the sulfide solid electrolyte, a binder, and an organic solvent to prepare a slurry, which is then applied to a substrate and dried.

[0016] The negative electrodes 4 and positive electrodes 7 are alternately stacked with solid electrolyte layers 8 interposed therebetween to form an all-solid-state battery stack 10. The solid electrolyte layer 8 is interposed between the negative electrode 4 and the positive electrode 7 to form one battery cell 9. The all-solid-state battery stack 10 includes a plurality of battery cells 9. The number of battery cells 9 may be one. In each battery cell 9, charging and discharging are performed by exchange of alkali metal ions (e.g., Li ions) between the negative electrode 4 and the positive electrode 7 via the solid electrolyte layer 8.

[0017] <<Manufacturing Method>> Next, a manufacturing method of the all-solid-state battery 1 according to this embodiment will be described with reference to the flowchart shown in FIG. 4. Note that other processes may be included between the steps in the flowchart of FIG. 4. The all-solid-state battery 1 is manufactured using various devices, such as a device for stacking the negative electrode 4, the positive electrode 7, and the solid electrolyte layer 8, a pressure device for pressurizing the all-solid-state battery stack 10, a device for discharging the all-solid-state battery stack 10, and a welding device for welding the current collector and the tab lead. Hereinafter, these devices will be collectively referred to as manufacturing devices.

[0018] In step ST1, the manufacturing equipment places a cathode 7 with a solid electrolyte layer 8. For example, the cathode 7 with a solid electrolyte layer 8 is placed, in which the solid electrolyte layer 8 is pre-laminated on the cathode layer 5. The manufacturing method involves stacking the cathode 7 and the solid electrolyte layer 8 so that the cathode layer 5 and the solid electrolyte layer 8 are in contact with each other and applying pressure. After pressing, the substrate of the solid electrolyte layer 8 is removed, thereby transferring the solid electrolyte layer 8 to the cathode 7. The cathode 7 with the solid electrolyte layer 8 can be obtained by this manufacturing method. Note that the manufacturing method according to the first embodiment is not limited to this. For example, the solid electrolyte layer 8 may be provided on the anode 4 instead of the cathode 7. In this case, step ST1 simply becomes a step of placing the cathode 7, and step ST2, described later, becomes a step of placing the anode 4 with the solid electrolyte layer 8. Alternatively, the solid electrolyte layer 8 may be prepared separately from the cathode 7 and the anode 4. In this case, for example, a step of placing the solid electrolyte layer 8 may be provided between the step of placing the cathode 7 (step ST1) and the step of placing the anode 4 (step ST2). Next, in step ST2, the manufacturing equipment places the negative electrode 4 at a position facing the positive electrode 7 in the stacking direction with the solid electrolyte layer 8 interposed therebetween.

[0019] Steps ST1 and ST2 constitute the stacking process for one battery cell. Steps ST1 and ST2 are repeated a preset number of times (i.e., a predetermined number of times). The predetermined number of times corresponds, for example, to the number of stacked battery cells 9 (see FIG. 3 ). As a result, as shown in FIG. 5 , an unbonded laminate 10′ is formed in which an anode 4 containing Li metal or Li alloy as the anode layer 2, a solid electrolyte layer 8, and a cathode 7 are repeatedly arranged in the stacking direction. More specifically, an unbonded laminate 10′ is formed in which a cathode current collector 6, a cathode layer 5, a solid electrolyte layer 8, an anode layer 2, and an anode current collector 3 are stacked in this order. In a plan view, the area of ​​the anode layer 2 is larger than the area of ​​the cathode layer 5. In a plan view of the unbonded laminate 10′, the entire cathode layer 5 is arranged to overlap the anode layer 2. The direction in which the positive electrode current collector 6 to the negative electrode current collector 3 are stacked is the vertical direction on the paper surface of Fig. 5, and this direction is referred to as the stacking direction. In the following description, the manufacturing method of the all-solid-state battery 1 according to the first embodiment may be described using as an example a case in which the number of stacked battery cells 9 is one.

[0020] Next, in step ST3 of FIG. 4 , the manufacturing equipment applies pressure to the unbonded laminate 10′. For example, as shown in FIG. 5 , the manufacturing equipment applies pressure P1 to the unbonded laminate 10′ at least in the stacking direction. The pressure P1 shown in FIG. 5 is equal to or greater than the yield stress of Li metal, e.g., 5 MPa or greater. The yield stress of Li metal refers to the stress at which Li metal begins to become plastic. This pressure application causes high pressure bonding between the anode layer 2 and the solid electrolyte layer 8, and between the solid electrolyte layer 8 and the cathode layer 5, to form the all-solid-state battery laminate 10. When viewed from above, the cathode layer 5 is disposed so that the entire anode layer 2 overlaps the anode layer 2. The all-solid-state battery laminate 10 is the laminate after pressure application. When the all-solid-state battery laminate 10 after pressure application and the unbonded laminate 10′ are not distinguished from each other, they are simply referred to as laminates.

[0021] By this molding, the anode layer 2 made of Li metal or Li alloy is pressure-bonded to the solid electrolyte layer 8. Therefore, each battery cell 9 included in the all-solid-state battery stack 10 is formed in a charged state. For example, each battery cell 9 included in the all-solid-state battery stack 10 is formed in a state of 100% SOC or a high SOC.

[0022] 6 is in a state where electrochemical processes such as charging and discharging have not yet been performed. In this state where electrochemical processes have not yet been performed, the anode layer 2 has both a facing portion 21 facing the cathode layer 5 and a non-facing portion 22 not facing the cathode layer 5.

[0023] 5 is also in a state where electrochemical processes such as charging and discharging have not yet been carried out. Although reference numerals are not shown in the unbonded laminate 10′, the negative electrode layer 2 similarly has both a facing portion 21 facing the positive electrode layer 5 and a non-facing portion 22 not facing the positive electrode layer 5.

[0024] Next, in step ST4 of Fig. 4, the manufacturing equipment performs tab joining. For example, the manufacturing equipment joins the negative electrode current collector 3 to the negative electrode tab lead 11 (see Fig. 3). The manufacturing equipment also joins the multiple positive electrode current collectors 6 to the positive electrode tab lead 12 (see Fig. 3). These joining steps are performed by welding, for example. The welding method is not particularly limited, but examples include welding using an ultrasonic welder and laser welding.

[0025] Next, in step ST5 of Fig. 4, the manufacturing apparatus performs a discharging process. In the discharging process, the manufacturing apparatus performs an initial discharging operation on the all-solid-state battery stack 10 formed in a charged state. For example, a discharging operation is performed on all battery cells 9 included in the all-solid-state battery stack 10 via the negative electrode tab lead 11 and positive electrode tab lead 12 shown in Fig. 3. In the discharging operation, in each battery cell 9, Li ions move from the negative electrode 4 through the solid electrolyte layer 8 to the positive electrode 7 and are occluded in the positive electrode layer 5. When the discharging operation is performed, the Li metal or Li alloy as the negative electrode layer 2 decreases as the discharge progresses. When the discharge progresses to an SOC of 0%, the Li metal or Li alloy as the negative electrode layer 2 is almost completely depleted.

[0026] The initial discharge operation will be described in more detail below with reference to FIG. 6 . The manufacturing apparatus performs the initial discharge operation while applying a stimulus A to the non-facing portion 22 of the negative electrode layer 2 in order to promote the discharge reaction of the non-facing portion 22. More specifically, the manufacturing apparatus performs the discharge operation while applying a stronger stimulus A to the non-facing portion 22 of the facing portion 21 and the non-facing portion 22. A portion of the facing portion 21 (e.g., a portion adjacent to the non-facing portion 22) may receive the same level of stimulus as the non-facing portion 22. However, the stimulus received by another portion of the facing portion 21 (e.g., a central portion in a plan view) is smaller than the stimulus received by the non-facing portion 22. Furthermore, when viewed as a whole, the facing portion 21 receives a smaller stimulus than the non-facing portion 22.

[0027] By applying a larger amount of stimulus A to the non-facing portion 22, the electrochemical activity of the non-facing portion 22 can be increased. By performing a discharging operation in such a state, the reactivity of the non-facing portion 22 can be increased, and the reaction can proceed preferentially from the non-facing portion 22 (see the all-solid-state battery stack 10 shown in the center of the left and right of FIG. 6 ). Note that the reaction also proceeds in the facing portion 21 due to the discharging operation. When the discharge proceeds to an SOC of 0%, the Li metal or Li alloy in both the facing portion 21 and the non-facing portion 22 of the anode layer 2 is almost gone (see the all-solid-state battery stack 10 shown on the right side of FIG. 6 ).

[0028] The stimulus A is, for example, heat. As shown in FIGS. 7 and 8 , a plate-shaped member 101A provided with a heater 101 and a plate-shaped member 102A provided with a heater 102 are prepared. The heaters 101 and 102 are, for example, electric heating wires, and are, for example, at a temperature of about 60° C. during use, although this is not a limitation. The material constituting the plate-shaped members 101A and 102A is not particularly limited, but is preferably made of a material with a low thermal conductivity. The plate-shaped members 101A and 102A may also function as pressure plates that apply pressure to the all-solid-state battery stack 10 during the initial discharge operation.

[0029] As shown in FIG. 8 , the heaters 101 and 102 are provided in an annular shape in a planar view so as to face the unopposed portion 22 located at the periphery of the all-solid-state battery stack 10. As shown in FIG. 7 , the plate-shaped member 101A is disposed on the upper surface side of the all-solid-state battery stack 10, and the plate-shaped member 102A is disposed on the lower surface side of the all-solid-state battery stack 10. With the plate-shaped members 101A and 102A disposed, the heaters 101 and 102 face the unopposed portion 22 and apply heat to the unopposed portion 22 along the stacking direction. The heaters 101 and 102 may continue to apply heat to the unopposed portion 22 throughout the entire discharge operation. This results in a temperature distribution within the plane of the all-solid-state battery stack 10 in a planar view. More specifically, a temperature distribution is generated within the plane of the all-solid-state battery stack 10 in a planar view, with the temperature higher closer to the edge.

[0030] Similarly, when the all-solid-state battery stack 10 includes a plurality of layers of battery cells 9, the plate-shaped member 101A is disposed on the upper surface side of the all-solid-state battery stack 10, and the plate-shaped member 102A is disposed on the lower surface side of the all-solid-state battery stack 10. In this case, a temperature distribution may occur in the unopposed portion 22 along the stacking direction. However, even in such a case, a temperature distribution can be generated in the plane of the negative electrode layer 2 in a plan view in all of the battery cells 9.

[0031] 9 and 10 , instead of the heaters 101 and 102, a heater 103 that heats the side surface of the all-solid-state battery stack 10 may be provided. The heater 103 applies heat to the unopposed portion 22 in a direction perpendicular to the stacking direction. When the all-solid-state battery stack 10 includes a plurality of layers of battery cells 9, heat is applied to the unopposed portion 22 in a direction perpendicular to the stacking direction, making it difficult for a temperature distribution to occur in the unopposed portion 22 along the stacking direction.

[0032] The stimulus A is, for example, pressure. As shown in FIG. 11 , a pair of plate-shaped members 201 and 202 are prepared. The plate-shaped members 201 and 202 are pressure plates that apply pressure P2 to the all-solid-state battery stack 10 during the initial discharge operation. The plate-shaped member 201 is disposed on the upper surface of the all-solid-state battery stack 10, and the plate-shaped member 202 is disposed on the lower surface of the all-solid-state battery stack 10. The pressure P2 is lower than the pressure P1, for example, approximately 0.5 MPa or more and 20 MPa or less. The plate-shaped members 201 and 202 are made of, for example, metal. The discharge operation is performed with a frame member 203 disposed in a position surrounding the positive electrode layer 5 in a plan view. The frame member 203 is disposed between the lower surface of the solid electrolyte layer 8 and the upper surface of the positive electrode current collector 6 and prevents the edge of the solid electrolyte layer 8 from cracking due to the pressure applied by the plate-shaped member 201. The frame member 203 may be removed after the discharge operation is completed.

[0033] The plate-shaped member 201 has a flat plate portion 201a and a protruding portion 201b protruding from the flat plate portion 201a in a planar view. The plate-shaped member 202 does not have a protruding portion. The protruding portion 201b of the plate-shaped member 201 is provided in an annular shape in a planar view so as to face the unopposed portion 22 located on the periphery of the all-solid-state battery stack 10. An initial discharge operation is performed with the plate-shaped member 201 positioned so that the protruding portion 201b faces the all-solid-state battery stack 10. With the plate-shaped members 201 and 202 positioned, the protruding portion 201b faces the unopposed portion 22 and applies pressure to the unopposed portion 22 along the stacking direction. The plate-shaped members 201 and 202 continue to apply pressure to the unopposed portion 22 throughout the discharge operation. The area of ​​the flat plate portion 201a where the protruding portion 201b is not provided does not contact the all-solid-state battery stack 10. As a result, a pressure distribution occurs within the plane of the all-solid-state battery stack 10 in plan view. More specifically, a pressure distribution occurs within the plane of the all-solid-state battery stack 10 in plan view, such that the pressure is higher closer to the edges. Note that, even in the case where the all-solid-state battery stack 10 includes a plurality of layers of battery cells 9, the plate-shaped member 201 is similarly arranged on the upper surface side of the all-solid-state battery stack 10, and the plate-shaped member 202 is similarly arranged on the lower surface side of the all-solid-state battery stack 10.

[0034] 12 , a plate-shaped member 204 without a protruding portion may be provided instead of the plate-shaped member 201. In this case, an elastic member 205 is interposed between the plate-shaped member 204 and the all-solid-state battery stack 10, and the initial discharge operation is performed. The elastic member 205 includes a first elastic member 205a and a second elastic member 205b having a higher elastic modulus than the first elastic member 205a. The second elastic member 205b is provided so as to surround the first elastic member 205a in a planar view. The second elastic member 205b is provided in an annular shape in a planar view so as to be able to face the unfaced portion 22 located on the periphery of the all-solid-state battery stack 10. When the elastic member 205 is arranged, the first elastic member 205a faces the facing portion 21, and the second elastic member 205b faces the unfaced portion 22. When the plate-like members 201, 202 press the all-solid-state battery stack 10 in the stacking direction, a higher pressure is applied to the non-facing portion 22 facing the second elastic member 205b than to the facing portion 21 facing the first elastic member 205a due to the difference in elastic modulus. Although not limited to this, for example, a pressure of approximately 3 MPa is applied to the non-facing portion 22, and a pressure of approximately 1 MPa is applied to the facing portion 21. This results in a pressure distribution within the surface of the all-solid-state battery stack 10 in a planar view. More specifically, a pressure distribution is generated within the surface of the all-solid-state battery stack 10 in a planar view, such that the pressure is higher closer to the edges. The elastic member 205 may be removed once the discharging operation is complete. The all-solid-state battery stack 10 may also include multiple layers of battery cells 9.

[0035] <Other Embodiments> As described above, the present invention has been described with reference to embodiments and modifications. However, the descriptions and drawings that form part of this disclosure should not be understood as limiting the present invention. Various alternative embodiments and modifications will become apparent to those skilled in the art from this disclosure. It goes without saying that the present technology includes various embodiments not described herein. Various omissions, substitutions, and / or modifications of components may be made without departing from the spirit of the above-described embodiments. Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0036] The present invention can also employ the following configurations. Furthermore, the following configurations can be combined with each other. (1) A method for manufacturing an all-solid-state battery, comprising: forming a laminate including a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, an anode layer having a larger area than the positive electrode layer in a planar view and containing lithium metal or a lithium alloy, and an anode current collector; and discharging the laminate, wherein the anode layer has a facing portion facing the positive electrode layer and a non-facing portion not facing the positive electrode layer. The discharging step is performed while applying a stronger stimulus to the non-facing portion of the facing portion and the non-facing portion. By applying a larger amount of stimulus A to the non-facing portion, the electrochemical activity of the non-facing portion not facing the positive electrode layer can be increased. By performing the discharging operation in such a state, the reactivity of the non-facing portion can be increased, and the reaction can proceed preferentially from the non-facing portion. Therefore, the negative electrode layer 2 is less likely to remain on the negative electrode side (negative electrode current collector 3 side) during the initial discharge operation, which prevents a decrease in discharge efficiency and a decrease in the utilization rate of the negative electrode. (2) The stimulus may be heat. By applying heat as a stimulus to the non-facing portion 22, the electrochemical activity of the non-facing portion 22 can be increased. (3) The stimulus may be pressure. By applying pressure as a stimulus to the non-facing portion 22, the electrochemical activity of the non-facing portion 22 can be increased. (4) The stimulus may be applied along the stacking direction. Various stimuli such as heat and pressure can be applied. (5) The stimulus may be applied along a direction perpendicular to the stacking direction. This makes it less likely that a distribution (e.g., a temperature distribution) will occur in the non-facing portion 22 along the stacking direction.

[0037] 1... all-solid-state battery, 2... negative electrode layer, 3... negative electrode current collector, 4... negative electrode, 5... positive electrode layer, 6... positive electrode current collector, 7... positive electrode, 8... solid electrolyte layer, 9, 109... battery cell, 10'... laminate, 10... all-solid-state battery laminate, 11... negative electrode tab lead, 12... positive electrode tab lead, 21... facing portion, 22... non-facing portion, A... stimulus, P1, P2... pressure

Claims

1. A method for manufacturing an all-solid-state battery, comprising: a step of forming a laminate in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer having an area in a planar view larger than that of the positive electrode layer and containing lithium metal or a lithium alloy, and a negative electrode current collector are stacked; and a step of discharging the laminate, wherein the negative electrode layer has a facing portion that faces the positive electrode layer and a non-facing portion that does not face the positive electrode layer, and the step of discharging is performed while applying a stronger stimulus to the non-facing portion of the facing portion and the non-facing portion.

2. The method for producing an all-solid-state battery according to claim 1, wherein the stimulus is heat.

3. The method for producing an all-solid-state battery according to claim 1, wherein the stimulus is pressure.

4. The method for producing an all-solid-state battery according to claim 2 or 3, wherein the stimulus is applied along the stacking direction.

5. The method for producing an all-solid-state battery according to claim 2, wherein the stimulus is applied in a direction perpendicular to the stacking direction.

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